Shear mechanism.



No. 630,68l. Patented Aug. 3, I899.

. w. A. G'ILLMEN.

SHEAR MECHANISM.

(Application filed Dec. 2, 1898.!

(No Model.)

WITNESSES: INVENTOR,

a. MW

UNITED STA ES PA ENT men.

WILLIAM A. GILLMEN, OF MCKEESPORT, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO ALAN D. WOOD, OF ALLEGHENY, PENNSYLVANIA.

SHEAR MECHANISM.

SPECIFICATION forming part of Letters Patent N 6. 630,681, dated August 8, 1899. Application filed December 2, 1898. Serial No. 698,050. (No model.)

To all whom it may concern.-

Be it knownthat I, WILLIAM A. GILLMEN, a citizen of the United States, residing at Me- Keesport, in the county' of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Shear Mechanism, of which improvements the following is'a specification.

It has heretofore been customary to secure the blades to the heads of shear mechanism by means of a series of bolts passing through holes in the heads and blades or knives. As it is necessary to make the blades as hard as possible without rendering them brittle, the bolt-holes must be formed in the blades before being subjected to the tempering or hardening process. This hardening process produces such changes in therelative dimensions of the blades that the bolt-holes therein will not register with the holes in the heads of the shear mechanism so that the holes in the blades or heads must be chipped or reamed out to permit of the attachment of the blades to the heads. It has been attempted to overcome this objectionable feature by providing clamps which were adapted to secure the blades to the heads without the employment of bolts passing through the blades. In such construction the blades were. made of such irregular shape in cross-section and with such varying dimensions that it was practically impossible to keep the blades from twisting out of shape during the hardening and tempering thereof.

The object of this invention is to provide a blade of such shape and relative dimensions that there will not be any material distortion during hardening and tempering and will require only a slight back out or loosening of the clamping nuts or bolts to release the blades from the head. The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification, Figure 1 is a sec tional elevation of a portion of the head of a shear mechanism having my improved blade and clamping device attached thereto. Fig. 2 is asectional detail view of the clampingjaw, and Fig. 3 is a similar view of the blade.

In the practice of my invention the head 1 is of theusual shape or construction as regards the portion to which the blade is to be attached and is provided with a bearing-shoulder 2 and with a series of vertical slots 3, through which the fastening-bolts pass. The blade consists of the substantially rectangular body portion 4 and the supporting-rib 5, extending along the inner edge diagonally opposite the cutting edge. The inner face of the rib is flush with the corresponding face of the body portion; but its outer face is undercut or so inclined as to form an acute angle with the upper face of the body portionin other words, the rib has a half-dovetail shape in cross-section. The clamping-plate consists of the body portion 6, substantially rectangular in cross-section and a rib 7, similar to the rib 5 of the blade, but formed along the lower outer edge of the body portion 6. "As shown in Fig. l, the ribs onthe blade and clamping-plate are made of equal dimensions, so that all the portions of the upper face of the blade have a uniform bearing against all portions of the under face of the clampingplate, and that blade is held in position by the inclined inner face of the rib 7 bearingagainst the oppositely-inclined outer face of the rib 5 of the blade. The clamping-plate is held to the head by means of bolts 8 passing through holes in the clamping-plate and the slots 3 in the head.

When my improvements are newly applied to shear mechanism, the blade and clampingplate are so proportioned that the blade will project a short distancebelow the head when the upper face of the clamping-plate bears against the shoulder 2 of the head. As the lower face of the blade is worn away by grinding, &c., thin metal plates or wedges are inserted between the clamping-plate and the shoulder 2, the slots in the head permitting of this downward adjustment of the blades and clamping-plate.

To remove the blades from the head, the nuts on the bolts need be slackened only sufficently far to permit the broader upper edge of the rib 5 to drop down between the rib 7 and the head, and this is one of the distinguishing characteristics of '.1ny -inventionthat the blades can be removed and another substituted without the entire removal of the holding-bolts. By reason of the regularity in shape of the blade and relative size and location of the parts thereof there is little liability of distortion in hardening and tempering.

As my improvement can be applied to either the upper or lower heads of a shear mechanism, the terms upper and lower are only relatively employed.

I claim herein as my invention 1. The combination of a head of a shear mechanism, a clamping-plate provided with a rib having an inclined inner face forming with'the face of the head a dovetail recess, a blade provided with a rib havinga correspondingly-inclined outer face, and means for securing the clamping-plate to the head, substantially as set forth.

2. The combination of the head of a shear mechanism having a shoulder or abutment and a series of slots below the shoulder, a clamping-plate adapted to bear against said shoulder and provided along its outer edge with a rib having an inclined inner face forming with the face of the head a dovetail recess, a blade provided with a rib having a correspondingly inclined outer face, and bolts passing through-the clamping-plate and the slots in the head, substantially as set forth.

3. A blade for a shear mechanism, consisting of a bodyportion substantially rectangular in cross-section and provided with a rib along the edge diagonally opposite the cutting edge, said rib having an inclined face for engagement with the undercut inner face of the clamp, substantially as set forth.

In testimony whereof I have hereunto set my hand.

WILLIAM A. GILLMEN.

\Vitnesses-z DARWIN S. WoLco'rT, F. E. GAITHER. 

